\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[english]{babel}



\usepackage{float}








\begin{document}

\title{Towards the direct simulation of the quasi-biennial oscillation in a
global storm-resolving model}



\author[1]{Henning Franke}%
\author[1]{Marco A. Giorgetta}%
\affil[1]{Max Planck Institute for Meteorology}%


\vspace{-1em}



  
  \date{May 16, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
This study presents the first attempt to directly simulate a full cycle
of the quasi-biennial oscillation (QBO) in a global storm-resolving
model (GSRM) that explicitly simulates deep convection and gravity waves
instead of parameterizing them. Using the Icosahedral Nonhydrostatic
(ICON) model with horizontal and vertical resolutions of about 5 km and
400 m, respectively, we show that an untuned state-of-the-art global
storm-resolving model is already on the verge of simulating a QBO-like
oscillation of the zonal wind in the tropical stratosphere for the right
reasons. ICON shows overall good fidelity in simulating the QBO momentum
budget and the downward propagation of the QBO jets in the upper QBO
domain (25 km--35 km). In the lowermost stratosphere, however, ICON does
not simulate the downward propagation of the QBO jets to the tropopause.
This is the result of a pronounced lack of QBO wave forcing, mainly on
planetary scales. We show that the lack of planetary-scale wave forcing
in the lowermost stratosphere is caused by an underestimation of the
planetary-scale wave momentum flux entering the stratosphere, which is
too weak by 20\%--40\%. We attribute this lack of planetary-scale wave
momentum flux to a substantial lack of convectively coupled equatorial
waves in the tropical troposphere. Therefore, we conclude that in the
present global storm-resolving model, simulating a realistic
spatio-temporal variability of tropical deep convection, in particular
convectively coupled equatorial waves, is currently the main roadblock
towards simulating a reasonable QBO.%
\end{abstract}%



\sloppy




\selectlanguage{english}
\FloatBarrier
\end{document}

